The present invention relates in general to connecting electrical signals into and out of a circuit. More specifically, the present invention relates to systems, methodologies and resulting bump-bonded interfaces configured to execute the direct transfer of electronic signals into and out of cryogenic electronics in a manner that eliminates the need for intermediary electrical connection mechanisms such as wire bond connections, and the like.
Electronic components may be connected together through different techniques. One such method is through wire bonding. Wire bonding is a well-known technique for forming electrical interconnections between an electronic component (e.g., a printed circuit board (PCB), a packaged or unpackaged integrated circuit (IC), etc.) and other components (e.g., external components, card sockets, microwave connectors, chip carriers, etc.). In wire bonding, a length of small diameter soft metal wire (e.g., gold (Au), copper (Cu), silver (Ag), aluminum (Al), and the like) is attached or bonded without the use of solder to a compatible metallic surface or pad mounted on a PCB or an IC/chip carrying substrate. The actual bond between the wire and the pad can be formed in a variety of ways, including the use of thermo-compression, thermo-sonic and ultrasonic techniques.
Components such as IC/chip carriers can be designed to reliably operate under a variety of conditions, including, for example, cryogenic conditions. The term “cryogenics” refers generally to the branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures. The term “reliability” is used in electronics to describe the probability that a component operating under specified conditions will perform satisfactorily for a given period of time. Although wire bonding is widely used in the fabrication of electronic systems, the additional wire bond hardware, particularly in cryogenic electronic applications, is manually intensive to fabricate, suffers from low temperature CTE (coefficient of thermal expansion) mismatches, is difficult to reliably repeat, causes signal path problems, increases costs, adds bulk and in the case of microwave/radio frequency (RF) introduces extraneous microwave cavity modes.